There is one more thing that could be different. These heavier rears have locators to support the back side of the third member. We call them dogs. I'm not so sure I would trust anything from the LKQ web site. LKQ is an investment group that bought a bunch of salvage yards and are closing them now because they don't know the salvage business. In fact I bought a trailer load of Merritor rears at their closing auction at West Monroe, LA back in December. I would call someone who has been in the salvage business all their lives. Possibly someone like Doug Geiger at Geiger Truck Salvage in Watseka, IL or Rod Thompson at Thompson Motors in Wykoff, MN. These guys have been doing salvage all their lives and don't need books.